In a liquid crystal display device (display device) that incorporates a non-light-emitting liquid crystal display panel (display panel), usually, also a backlight unit (illumination device), which supplies light to the liquid crystal display panel, is incorporated. There are various kinds of light sources for the backlight unit. For example, in a case of the backlight unit disclosed in a patent document 1, the light source is an LED (Light Emitting Diode).
In this backlight unit, as shown in FIG. 20, a lens 110, which diffuses light from an LED mounted on a mounting substrate 120, is disposed (here, a module, which includes the LED, the lens 110 and the mounting substrate 120, is called a light-emitting module mj).